ABSTRACT There is now consensus in the drug treatment field that substance dependence requires long-term interventions that extend well beyond formal treatment. Sober living houses (SLHs) are alcohol- and drug-free recovery homes that help individuals with drug dependence maintain long-term abstinence after completion of treatment or release from incarceration. In some cases they serve as an alternative recovery option for individuals who do not want to seek help from a formal treatment program. Studies by our research team were the first to document excellent outcomes for SLH residents, which were maintained over an 18-month follow- up period. Among a number of important results was the finding that severity of psychiatric symptoms predicted worse outcome and social support for recovery predicted better outcome. It is striking that studies of recovery from addiction have ignored how these two factors interact to affect outcome. We hypothesize the destructive impact of psychiatric symptoms on resident outcomes will be mitigated by social support for recovery. A variety of other potential moderators will be explored as well, including receipt of mental health services, general social support, demographics and type of drug dependence. Most studies examining predictors of recovery from addictive disorders are limited to baseline measures. The proposed study will be the first to test how interactions between psychiatric symptoms and social support operate longitudinally to affect relapse. The study will consist of a secondary analysis of the 323 SLH residents who were interviewed at baseline and 6-, 12- and, 18-month follow-up. Although the parent grant included an aim assessing how a composite, global measure of psychiatric severity (BSI Global Severity Index) impacted drug use, no analyses examined potential moderators or mediators. In addition, no aims addressed the impact of different types of psychiatric symptoms. The proposed study will track trajectories of nine BSI scales, each measuring a specific psychiatric symptom (e.g., depression, anxiety, psychosis, obsessive compulsive, etc.) and their associations with relapse over 18 months. The study will be the first that examines trajectories of psychiatric symptoms among substance dependent persons using a longitudinal design outside the context of formal treatment. Although the parent grant found the GSI scale improved over time, the clinical significance was modest. The proposed study will identify which of the 9 BSI scales measuring different dimensions of psychiatric symptoms improved, which were unchanged, and which may have become worse. The proposed study will also assess the types of psychiatric symptoms for which participants received treatment, the types of symptoms that were undetected or untreated and how receipt of treatment affected outcome. Study findings will have implications for recognizing and addressing psychiatric symptoms in SLHs as well as broader implications for sustaining long term recovery in the community.